The armour at this point masses some 32 kg, a figure disturbingly close to the classical "70lb" of infantry men throughout the ages. In itself, this isn't an improbable loading especially as this mass is closely connected to the body and is thus well-distributed. The major drawback for the novice wearer is that the centre of gravity is noticeably higher than in a normal clothed state.
To avoid problems when fighting on foot, this unusual state of balance coupled with the use of authentic footwear requires care and experience in a variety of conditions. However, all this extra mass is an advantage in the push and shove of shield-wall fighting.
One disadvantage I've found is that if knocked down onto my back whilst wearing all the above, the reduced torso flexibility makes it virtually impossible to sit up - you have to (vulnerably) roll over onto your knees and elbows in order to stand again. Still, you would be unlikely to be killed once the ground: a knight would be worth ransoming, compared to the average infantryman. 
This may be one of the reasons why we see a trend towards greater ostentation and heraldic display through the 13th century, along with the appearance of aillettes, such as those depicted on the left. In practice, I've noticed in the fury of fighting alongside people, it is easy to lose where you are, relative to others. Things move quickly, and the very real fog of war confuses things. Therefore wearing advertising hoardings such as these, fighting under a banner, and drawing on battle-cries pertinent to your family may have been extra ways to ensure you and your retinue stayed together and fought together in the heat of battle.